1972 c20 running problems

[thetucks]

I attempted to adjust the mixture screws. But I can't figure it out. I turned the first one in a turn and it went down just a little so turned it back out and it never went above where it was. Im lost. I checked the amount of turns and they are 5 turns out. I thought they are only suppose to be like 3?
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[geezer#99]

THey should be 1.5 to 2 turns out. Get a vacuum gauge and set to highest vacuum. A good vac gauge is only 10-20 bucks. Shut motor off. SEt them both at 2 turns. Start truck then adjust from there. A quarter turn at a time. Alternate from one to the other. If it won't run at a couple turns out you could have a vacuum leak. Also set your idle as low as possible too with the motor warm.

[Mikey17]

id say around 550-750 rpm is a good idle, and with your carb you turn one screw until you notice a fairly good drop in idle speed then 1 and 1/4 turn back out. then do the same for the second one. do this 2 or 3 times and you should be good.

[thetucks]

ok I warmed the truck up. set both screws to 2 turns out. started the truck and it died. so I checked the idle. I had it turned so far down that is why it was dying. I turn it up and it runs smooth now. I still have to go for a test drive but its a lot better then 5 turns out like it was before. Ill buy a vacume gauge and fine tune it.

[ls1nova71]

If your brake pedal is going to the floor when you push it slowly but if firm when you push it fast, is usually the master cylinder leaking internally. If you press hard on the pedal and hold it van you feel it slowly go down?
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[thetucks]

Ill give that a try, thanks.

[thetucks]

I tried to hold the brake pedal down with the truck off. it holds. I tried to hold the brake pedal down with the truck on. it holds. now what?

[thetucks]

im going to get back on this project tomorrow nite. Ive started the truck a few times over the past few weeks and it seems that its running too rich. I did buy a vaccum guage so I can check the carb adjustments correctly. but when the truck runs the exhaust is smelly and smokey. now im getting worried. I still have the brake problem also. could they just need to be bled?

[thetucks]

anyone??

[67mater]

you may NOW be looking at a rebuild if the fuel is leaking internally and you are starting "rich". If you still have th carb you rebuilt several times, you could swap back since you have the timing adjusted closer. Also be sure the choke is operating correctly, and opening fully. Does the smoky go away? just at start up? well after warmed up? If it's just at idle, you may need 1.5 turns out (we are again assuming you have ruled out any possible fuel or vacuum leaks). You also need to judge what color the "smoke" is; blue? white? black?

Oh, and enjoy the progress you've made!

[thetucks]

ok ive got another question. how do I know if I have the timing set right? I can set the timing correct but if I move the idle it moves the timing. I dont have a tach to set the idle from.

[thetucks]

bump